Does tourism have an impact on carbon emissions in Asia? An application of fresh panel methodology.

This research investigates the effects of tourism, GDP per capita, renewable energy, energy intensity, urbanization, and population on the environment in 40 Asian countries. Data from 1995 to 2019 are used in this analysis. Slope heterogeneity (SH), cross-sectional dependency (CSD), and the combination of level and first differenced stationary are all addressed using a new cross-sectionally autoregressive distributed lag (CS-ARDL) model in this work. Using Westerlund's cointegration method, these variables can be connected throughout time. To validate the findings, both augmented mean groups (AMG) and Common correlated effect mean groups (CCEMG) were utilized. The study results indicate that tourism helps slow the degradation of the natural environment. CO2 emissions increase as a result of variables such as population growth, energy use, and economic development. Only tourism and renewable energy can help cut CO2 emissions. As a consequence, CS-ARDL results are supported by results from AMG and CCEMG tests. Policymakers may be encouraged countries to adopt renewable energy and foster the expansion of the sustainable tourism industry.

Effect of Organic Amendments on Cadmium Bioavailability in Soil and its Accumulation in Rice Grain.

A pot trial was conducted during the boro (dry) season to evaluate the impact of six traditional organic amendments (OAs) on the growth of SL-8 rice variety in both agricultural and cadmium (Cd) stressed soil at 2% and 4% application rates. Traditional OAs used in the study were cow dung, mustard oil cake (MOC), rice husk, saw dust, tea leaf and vermi compost (VC). Except for cow dung all other OAs were found to remove 99% of Cd from the aqueous solution, while cow dung removed 95%. Rice grain grown in OA-added soil in all application rates contained less Cd than the control. A 2% application rate was found to be more effective in reducing both Cd bioavailability and Cd in grain. OA application in soil significantly influenced soil pH in all cases. Though both bioavailable Cd in soil and grain Cd were reduced by the OA addition, the Cd uptake tendency of SL-8 rice variety markedly increased because of Cd spiking in soil.

Effect of dye bath pH in dyeing of cotton knitted fabric with reactive dye (Remazol Yellow RR) in exhaust method: impact on color strength, chromatic values and fastness properties.

The significance of textile coloration is inevitable as coloration is a critical process and it can be affected by several parameters i. e. time, temperature, pH, and liquor ratio (M:L). This research reveals the behavior of different dye bath pH (2 to 12) on the basis of spectrophotometric characteristics and colorfastness using the most useable brand of reactive dye in Bangladesh i. e. Remazol Yellow RR. Earlier researches were performed on the basis of other coloration controlling factors i. e. temperature, time and liquor ratio (M:L) where pH acts as the dependent variable. However in this study, pH was taken as an independent variable where lower pH (2, 4 and 6), medium pH (8 and 10) and higher pH (12) were taken into consideration for verifying the dyeing performance. Meanwhile, the mentioned pH was achieved by adding acetic acid, soda ash and caustic soda respectively. In this study, the impact of pH is analyzed on the basis of color strength, chromaticity, hue angle, CIELAB color space, spectrophotometric image, reflectance percentage and color fastness tests i. e color fastness to rubbing, color fastness to wash, color fastness to perspiration, color fastness to light. Gradually elevated pH boosts up the color strength and chromaticity, at the same time downgrades of hue angle results orangish tone in the dyed fabric. Even more, the lightness of dyed fabric decreases and redness rises with the increment of dyebath pH which results in orangish red darker tone of dyed fabric. Consequently, fabric dyed at acidic dye bath pH exhibits higher resistance in case of color change and color staining from the dyed fabric and multifiber fabric respectively and vice versa.

Investigating the drying characteristics of Anthocephalus chinensis (Lam.) A. Rich ex Walp wood.

Anthocephalus chinensis (Lam.) A. Rich ex Walp is widely used as raw materials in particleboard and match industries in Bangladesh. The current study aimed to identify the drying characteristics of A. Chinensis wood for succeeding industrial usages. A compartment kiln dryer (heat and vent dryer) was used in this study. The drying characteristics and drying quality of A. Chinensis wood were measured. The boards reached 6-10% moisture content in 13 days from their green condition. The total proportions of the check, twist, and collapse in boards were 22.5, 32.5, and 7.3%, respectively. The volumetric shrinkage was 21.67%. Based on this study, further study may help to develop a complete drying schedule of A. Chinensis wood with fewer drying defects for application at industrial level.

A review on the treatment of dyes in printing and dyeing wastewater by plant biomass carbon.

Printing and dyeing wastewater (PDW) has characteristics of large amount of water, elevated content of residual dyes, poor biodegradability, high alkalinity and large change of water quality, making its treatment difficult. Development of efficient and economic PDW treatment technology has gained considerable interest in the field of environmental protection. Use of plant biomass carbon (PBC) for the adsorption of dyes is a feasible and economical technology. This review summarizes current literature discussing the preparation method and physicochemical characteristics of PBC prepared from different plant species, the effect of PBC on the removal of dyes, influencing factors affecting the removal, and relevant adsorption models. The shortcomings of current research and the direction of future research are also pointed out in the review.

Variations in cadmium accumulation among amon rice cultivars in Bangladesh and associated human health risks.

Rice consumption is one of the major cadmium (Cd) exposure routes for human. Bangladeshi people have historically subsisted on a rice-based diet; however, only a few reports have investigated Cd accumulation by different rice cultivars in Bangladesh. This study was designed to investigate the uptake and accumulation of Cd in different rice cultivars and associated health risks to humans eating rice. A pot experiment was conducted to grow eight amon rice varieties under control, 5 and 10 mg Cd/kg soil under open air conditions. After harvesting the Cd fractionation, bioavailable Cd and rice grain Cd content were determined. Cd spiked as Cd2+ enriched the Cd bioavailability to plant by 35% (in 5 mg/kg stress) and 85% (in 10 mg/kg stress). There were variations among the rice varieties in their ability to accumulate Cd in grain and this was found to be 15-fold higher under control conditions. Grain Cd content significantly differed among the rice varieties at each level of soil Cd. In this study, BR-52 emerged as the most Cd-safe cultivar followed by BR-75, Rani salut, BR-71, BR-49, BR-76, BR-87 and lastly, BINA-7. Most of the agronomic parameters of rice concerning yield were affected by both rice varieties and soil Cd level. In different rice varieties, rhizosphere pH increased through root exudation which ultimately produced equilibria among the five major soil Cd fractions so that Cd became bioavailable to plants. All rice varieties showed high hazard quotient (HQ) values under Cd stress conditions and posed a risk to human health. For noncarcinogenic health risk assessment through HQ, we recommend 0.1 mg Cd/kg rice grain be used as the maximum allowable concentration (MAC) in calculating health risk for Bangladeshi people.

Chromium Contamination from Tanning Industries and Phytoremediation Potential of Native Plants: A Study of Savar Tannery Industrial Estate in Dhaka, Bangladesh.

Tannery wastewater is a significant cause of chromium (Cr) contamination in land and water. This study assessed Cr contamination caused by the discharge of tannery wastewater in the Dhaleshwari River and identified possible native plants for phytoremediation of Cr. Water, soil and sediments samples were collected from upstream and downstream of the wastewater discharge channel of Savar tannery industrial estate situated on the bank of the river. Samples of root, stem, leaf and fruit of four selected plants (i.e., Eichhornia crassipes, Xanthium strumarium L., Cynodon dactylon, Croton bonplandianum Baill.) were also collected from those sampling points. The total Cr in acid digested samples were determined by flame atomic absorption spectrometry. High concentrations of Cr were detected in the water, soil and sediment samples collected near the wastewater discharge channel. Of all the plant species, Xanthium strumarium L. exhibited high translocation factors (TF) and bioconcentration factors (BCF) for Cr. Based on the findings of this study Xanthium strumarium L. is preferable as a native species for phytoremediation of Cr.

Does 'COVID-19 phobia' stimulate career anxiety?: Experience from a developing country.

Due to the outbreak of COVID-19 different forms of anxiety disorder have been seen in the mindset of people all around the world. This study aims to examine a structural relationship between 'COVID-19 phobia' and career anxiety among the workforce from the perspective of a developing country. This study collected survey data using a structured questionnaire by applying the scales of 'COVID-19 Phobia' and career anxiety. Study results reveal that the factors of the 'COVID-19 phobia' have a substantial influence on generating career-related anxiety among the workforce. Study results can play a vital role for the policymakers to formulate long-term policies to retrieve the world's economy. This study combined the concept of specific phobia and general anxiety disorder (GAD) to figure out how the global pandemic impacted peoples' mindsets and create career anxiety. The study results have theoretical and practical implications in many folds.

Adsorption of methylene blue onto betel nut husk-based activated carbon prepared by sodium hydroxide activation process.

In this study, activated carbon (AC) was prepared from agro-waste betel nut husks (BNH) through the chemical activation method. Different characterization techniques described the physicochemical nature of betel nut husks activated carbon (BNH-AC) through Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM), and pH point of zero charge. Later, the produced AC was used for methylene blue (MB) adsorption via numerous batch experimental parameters: initial concentrations of MB dye (25-250 mg/L), contact time (0.5-24 hours) and initial pH (2-12). Dye adsorption isotherms were also assessed at three temperatures where the maximum adsorption capacity (381.6 mg/g) was found at 30 °C. The adsorption equilibrium data were best suited to the non-linear form of the Freundlich isotherm model. Additionally, non-linear pseudo-second-order kinetic model was better fitted with the experimental value as well. Steady motion of solute particles from the boundary layer to the BNH-AC's surface was the possible reaction dynamics concerning MB adsorption. Thermodynamic study revealed that the adsorption process was spontaneous and exothermic in nature. Saline water emerged as an efficient eluent for the desorption of adsorbed dye on AC. Therefore, the BNH-AC is a very promising and cost-effective adsorbent for MB dye treatment and has high adsorption capacity.

Nitrate contamination of water in dug wells and associated health risks of rural communities in southwest Bangladesh.

Consumption of drinking water with high nitrate may pose a serious health hazard. This study examined nitrate concentration in the water of dug wells at the Jashore district of Bangladesh. A total of 58 water samples were collected from dug wells which are currently in use for drinking water. Concentrations of nitrate in the water range from 0.05 to 430 mg/l and from 0.24 to 206 mg/l respectively in the wet and dry seasons. About 17% and 14% of the samples during the wet and dry seasons respectively showed nitrate concentration above the WHO guideline value of 50 mg/l. The wells with high nitrate concentration showed health risks for adults and children. About 17% of the samples showed a health hazard index (HQnitrate) values above the acceptable limit (HQnitrate values > 1) for adults, in both the wet and dry seasons, whereas 26% and 33% of the water samples in the wet and dry seasons respectively showed HQnitrate values > 1 for children. Therefore, children are more likely to be affected by intaking nitrate-contaminated dug well water. Health risks of elevated nitrate concentration in the dug wells require proper attention to ensure reliable water supply.

Potential ecological risk of metal pollution in lead smelter-contaminated agricultural soils in Khulna, Bangladesh.

Lead smelters are important source of metal pollution. This study assessed ecological risks of three heavy metals (Pb, As, and Zn) in agricultural soils surrounding five Pb smelters from Khulna district in Bangladesh. A total of 81 surface soil samples collected within 500-m radius of the smelters were analyzed using an atomic absorption spectrophotometer (AAS). Concentrations of Pb, As, and Zn ranged within 6-3902, 1.8-9.6, and 45.4-563 mg/kg, respectively. About half of the Pb samples (~ 51%) exceeded soil quality standard target value (85 mg/kg), and the concentrations gradually decreased with horizontal distance from the smelter. The value of pollution index (PI) measured for Pb, As, and Zn varied respectively in the range of 0-195, 0.6-3.2, and 0.67-8.28, with mean values of 11.7, 1.9, and 3.92. The value of integrated pollution index (IPI) calculated for these metals remained between 0.58 and 66.2 with a mean of 5.7, and that designates ~ 96% of the sampled soils as moderately or highly contaminated. Potential ecological risk (PER) calculated for the metals indicate that all the samples were within low to moderate risk, and the descending order of PER of the metals was Pb > As > Zn.

Trace elements in rice grain and agricultural soils: assessment of health risk of inhabitants near a former secondary lead smelter in Khulna, Bangladesh.

Ingestion of food grain grown in metal-contaminated soils may cause serious effects on human health. This study assessed the concentrations of Pb, As, Cd and Zn in agricultural soils and in rice grains near a former secondary lead smelter in Khulna, Bangladesh. It analyzed 29 samples of surface soil and rice grain collected around 500 m of the smelter. Contamination factor (Cf), pollution load index and total hazard quotient (THQ) were calculated to determine ecological and human health risks. Cd was not detected in any of the samples. For the soil samples, medians of the concentrations of Pb, As and Zn were 109, 6.2 and 514 mg/kg, respectively. For the rice grain samples, medians of the concentrations of Pb, As and Zn were 4, 1.4 and 25 mg/kg fw, respectively. Medians of the concentrations of Pb and As in rice grain were higher compared to their maximum allowable limit (0.2 mg/kg), which indicate potential health risks to inhabitants near the Pb smelter. The mean values of Cf for Pb, As, and Zn were, respectively, 11.6, 2.1 and 7.4. For Pb, around 41% of the samples had Cf > 6 indicating very strong contamination. THQ values for Pb and As were greater than 1.0, which evinces the health hazards of these trace elements. Measures should be taken to prevent trace elements exposure from Pb smelter in the study area.

Evaluation of harvested rainwater quality at primary schools of southwest coastal Bangladesh.

Rainwater is a typical source of drinking water in the coastal areas of Bangladesh given the acute scarcity of drinking water. This study assessed potability of harvested rainwater of primary schools in southwest coastal Bangladesh. Water samples collected from 23 primary schools of Mongla sub-district under Bagerhat district were evaluated for indicator bacteria (total coliform (TC) and E. coli) and physico-chemical parameters (pH, electrical conductivity, turbidity, total dissolved solid, Fe, Zn, Pb, and Cd). Median concentrations of TC and E. coli in the harvested rainwater samples were respectively 3000 cfu/100 ml and 6 cfu/100 ml. However, concentrations of these indicator bacteria were lower at the consumption points which received a prior treatment. Concentration of Pb exceeded the maximum allowable limit for drinking water indicated by WHO and Bangladesh drinking water guideline value in 92% and 61% of the samples respectively, and the mean concentration was 0.08 mg/l (8 times higher than the WHO guideline value). The Pb contamination possibly occurred from the painting on roof railing and roof stair room. Therefore, consumption of harvested rainwater at primary schools may cause substantial health risk for the school-going children.

Mesoporous activated coconut shell-derived hydrochar prepared via hydrothermal carbonization-NaOH activation for methylene blue adsorption.

Mesoporous activated carbon was prepared using a hydrochar derived from coconut shell waste through hydrothermal carbonization and NaOH chemical activation process (COSHTC). Three sets of activated carbons were obtained with different hydrochar:NaOH impregnation ratios (1:1, 1:2, and 1:3). Among these ratios, 1:3 (COSHTC3) exhibited the optimum adsorption for methylene blue (MB). COSHTC3 adsorbed MB with an initial concentration of 25-250 mg/L at pH 3-11 and 30 °C. The adsorption isotherm of MB on COSHTC3 demonstrated that Langmuir isotherm could be better applied at a maximum monolayer adsorption capacity of 200.01 mg/g at 30 °C. The data was well fitted to the pseudo-second-order (PSO) kinetic model. These results show that the COSHTC3 prepared from low-cost agricultural waste (coconut shell) with average pore diameter 28.6 Å and surface area 876.14 m2/g acts as a better adsorbent for removal of cationic dyes and could pave the way for more low-cost adsorbents for dye removal.

Human hair-derived high surface area porous carbon material for the adsorption isotherm and kinetics of tetracycline antibiotics.

In this work, a human hair-derived high surface area porous carbon material (HHC) was prepared using potassium hydroxide activation. The morphology and textural properties of the HHC structure, along with its adsorption performance for tetracycline (TC) antibiotics, were evaluated. HHC showed a high surface area of 1505.11m2/g and 68.34% microporosity. The effects of most important variables, such as initial concentration (25-355mg/L), solution pH (3-13), and temperatures (30-50°C), on the HHC adsorption performance were investigated. Isotherm data analysis revealed the favorable application of the Langmuir model, with maximum TC uptakes of 128.52, 162.62, and 210.18mg/g at 30, 40, and 50°C, respectively. The experimental data of TC uptakes versus time were analyzed efficiently using a pseudo-first order model. Porous HHC could be an efficient adsorbent for eliminating antibiotic pollutants in wastewater.

Mesoporous activated carbon prepared from NaOH activation of rattan (Lacosperma secundiflorum) hydrochar for methylene blue removal.

Hydrothermal carbonization of biomass wastes presents a promising step in the production of cost-effective activated carbon. In the present work, mesoporous activated carbon (HAC) was prepared by the hydrothermal carbonization of rattan furniture wastes followed by NaOH activation. The textural and morphological characteristics, along with adsorption performance of prepared HAC toward methylene blue (MB) dye, were evaluated. The effects of common adsorption variables on performance resulted in a removal efficiency of 96% for the MB sample at initial concentration of 25mg/L, solution pH of 7, 30°C, and 8h. The Langmuir equation showed the best isotherm data correlation, with a maximum uptake of 359mg/g. The adsorbed amount versus time data was well fitted by a pseudo-second order kinetic model. The prepared HAC with a high surface area of 1135m2/g and an average pore size distribution of 35.5Å could be an efficient adsorbent for treatment of synthetic dyes in wastewaters.

Prevalence and risk factors of problematic internet use and the associated psychological distress among graduate students of Bangladesh.

A growing body of epidemiological literature suggests that problematic Internet use (PIU) is associated with a range of psychological health problems in adolescents and young adults. This study aimed to explore socio-demographic and behavioural correlates of PIU and examine its association with psychological distress. A total of 573 graduate students from Dhaka University of Bangladesh responded to a self-administered questionnaire that included internet addiction test (IAT), 12-items General Health Questionnaire and a set of socio-demographic and behavioural factors. The study found that nearly 24% of the participants displayed PIU on the IAT scale. The prevalence of PIU significantly varied depending on gender, socioeconomic status, smoking habit and physical activity (p < 0.05). The multiple regression analyses suggested that PIU is strongly associated with psychological distress regardless of all other explanatory variables (adjusted OR 2.37, 95% CI 1.57, 3.58). Further research is warranted to confirm this association by employing prospective study designs.

Validation of the Bangla Mindful Attention Awareness Scale.

This study tested the reliability, validity and factor structure of the Bangla translated Mindful Attention Awareness Scale (MAAS). Three scales - the Bangla MAAS, the short form of health 36 (SF-36) and the Internet Addiction Test (IAT) - were applied to 519 university students (51.4% female). Ninety-two participants were retested over a two weeks period to examine test-retest reliability. Consistent with previous studies, the results of exploratory and confirmatory factor analyses showed a single factor solution for the Bangla MAAS (χ2/df=222.243/90=2.47, CFI=0.93, NFI=0.87, and RMSEA=0.053). The temporal stability and internal consistency was also satisfactory (Cronbach's alpha 0.85). The Bangla MAAS was significantly and positively associated with SF-36 Mental and Physical health components and negatively with IAT scores. Additionally, MAAS scored significantly varied with the presence of physical illness and different living conditions, suggesting the validity of the tool. The Bangla version of the MAAS is, therefore, a valid and reliable tool to measure mindfulness among young Bangladeshi adults.

A thermogravimetric analysis of the combustion kinetics of karanja (Pongamia pinnata) fruit hulls char.

The combustion characteristics of Karanj fruit hulls char (KFH-char) was investigated with thermogravimetry analysis (TGA). The TGA outlined the char combustion thermographs at a different heating rate and isoconversional methods expressed the combustion kinetics. The Kissinger-Akahira-Sunose (KAS) and Flynn-Wall-Ozawa (FWO) methods authenticated the char average activation energy at 62.13 and 68.53kJ/mol respectively, enough to derive the char to burnout. However, the Coats-Redfern method verified the char combustion via complex multi-step mechanism; the second stage mechanism has 135kJ/mol average activation energy. The TGA thermographs and kinetic parameters revealed the adequacy of the KFH-char as fuel substrate than its precursor, Karanj fruit hulls (KFH).

Combustion kinetics of hydrochar produced from hydrothermal carbonisation of Karanj (Pongamia pinnata) fruit hulls via thermogravimetric analysis.

This study examined the combustion profile and kinetics of hydrochar produced from hydrothermal carbonisation (HTC) of Karanj fruit hulls (KFH). The HTC-KFH hydrochar combustion kinetics was investigated at 5, 10, and 20°C/min by thermogravimetric analysis. The kinetics model, Kissinger-Akahira-Sunose revealed the combustion kinetics parameters for the extent of conversion from 0.1 to 0.8; the activation energy varies from 114 to 67 kJ/mol respectively. The hydrochar combustion followed multi-steps kinetics; the Coats-Redfern models predicted the activation energies and pre-exponential constants for the hydrochar combustion zones. The diffusion models are the effective mechanism in the second and third zone.